Tank circuit structure and method of making the same

ABSTRACT

A tank circuit structure includes a first gate layer, a first substrate, a first shielding layer, a first conductive line and a first inter metal dielectric (IMD) layer. The first substrate is over the first gate layer. The first shielding layer is over the first substrate. The first conductive line is over the first shielding layer. The first IMD layer is between the first substrate and the first conductive line.

PRIORITY CLAIM

The present application is a divisional of U.S. application Ser. No.15/078,387, filed Mar. 23, 2016, now U.S. Pat. No. 10,720,387, issuedJul. 21, 2020, which is a continuation of U.S. application Ser. No.14/062,924, filed Oct. 25, 2013, now U.S. Pat. No. 9,754,874, issuedSep. 5, 2017, which are incorporated herein by reference in theirentireties.

BACKGROUND

Inductors are used in circuits to help regulate current flow through thecircuit. When a current flows through the inductor, energy is storedtemporarily in a magnetic field in the inductor. When the currentflowing through the inductor changes, a time-varying magnetic fieldwithin the inductor induces a voltage in the inductor which opposes thechange in current that created the magnetic field.

As technology nodes shrink, circuit sizes are reduced. Inductors occupya large area in a circuit design. As the circuit size decreases,proximity between the inductor or capacitor and the other devicesincreases. Furthermore, as metal lines in these components decrease insize, a resistance in the metal lines increases. The increasedresistance in turn lowers the quality (Q) factor of the inductors. Inaddition, inductors cause a magnetic flux to pass through the circuit.The magnetic flux is capable of introducing noise into other deviceswithin the circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments are illustrated by way of example, and not bylimitation, in the figures of the accompanying drawings, whereinelements having the same reference numeral designations represent likeelements throughout. It is emphasized that, in accordance with standardpractice in the industry various features may not be drawn to scale andare used for illustration purposes only. In fact, the dimensions of thevarious features in the drawings may be arbitrarily increased or reducedfor clarity of discussion.

FIG. 1A is a cross sectional view of an inductive capacitive (LC)structure in accordance with one or more embodiments;

FIG. 1B is a perspective view of an LC structure in accordance with oneor more embodiments;

FIG. 2A is a cross sectional view of an LC structure in accordance withone or more embodiments;

FIG. 2B is a cross sectional view of an LC structure in accordance withone or more embodiments;

FIG. 3A is a cross sectional view of an LC transmission line structurein accordance with one or more embodiments;

FIG. 3B is a perspective view of an LC transmission line structure inaccordance with one or more embodiments;

FIG. 4A is a cross sectional view of an LC transmission line structurein accordance with one or more embodiments;

FIG. 4B is a cross sectional view of an LC transmission line structurein accordance with one or more embodiments;

FIG. 5 is a cross sectional view of an LC structure in accordance withone or more embodiments;

FIG. 6A is a cross sectional view of an LC structure in accordance withone or more embodiments;

FIG. 6B is a cross sectional view of an LC structure in accordance withone or more embodiments;

FIG. 7 is a cross sectional view of an LC transmission line structure inaccordance with one or more embodiments;

FIG. 8A is a cross sectional view of an LC transmission line structurein accordance with one or more embodiments;

FIG. 8B is a cross sectional view of an LC transmission line structurein accordance with one or more embodiments;

FIG. 9A is a top view of a shielding plate in accordance with one ormore embodiments;

FIG. 9B is a top view of a shielding plate in accordance with one ormore embodiments; and

FIG. 10 is a flow chart of a method of making an LC structure inaccordance with one or more embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the disclosed subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are examples and are notintended to be limiting.

This description of the embodiments is intended to be read in connectionwith the accompanying drawings, which are to be considered part of theentire written description. In the description, relative terms such as“before,” “after,” “above,” “below,” “up,” “down,” “top” and “bottom” aswell as derivative thereof (e.g., “horizontally,” “downwardly,”“upwardly,” or the like) should be construed to refer to the orientationas then described or as shown in the drawing under discussion. Theserelative terms are for convenience of description and do not requirethat the system be constructed or operated in a particular orientation.Terms concerning attachments, coupling and the like, such as “connected”and “interconnected,” refer to a relationship wherein components areattached to one another either directly or indirectly throughintervening components, unless expressly described otherwise.

FIG. 1A is a cross sectional view of an inductive capacitive (LC)structure 100 in accordance with one or more embodiments. LC structure100 includes a first substrate 102, a second substrate 120, a firstconductive line 106 a, a second conductive line 106 b, a first shieldinglayer 114, a second shielding layer 130, a first gate layer 118, asecond gate layer 128, a switch 122, a first inter-metal dielectric(IMD) layer 104 and a second IMD layer 126. In some embodiments, LCstructure 100 is in a stacked configuration with a first LC tank circuitstructure 100 a located below the second substrate 120, and a second LCtank circuit structure 100 b located above the second substrate 120. Insome embodiments, first LC tank circuit structure 100 a and second LCtank circuit structure 100 b operate in a differential mode. In someembodiments, first LC tank circuit structure 100 a comprises firstsubstrate 102, first IMD layer 104, first conductive line 106 a, firstshielding layer 114 and first gate layer 118. In some embodiments,second LC tank circuit structure 100 b comprises second substrate 120,second IMD layer 126, second conductive line 106 b, second shieldinglayer 130 and second gate layer 128.

LC structure 100 includes a first substrate 102 and a first IMD layer104 over the first substrate 102. A first conductive line 106 a, a firstshielding layer 114 and a first gate layer 118 are each in first IMDlayer 104. In some embodiments, first IMD layer 104 is a multi-layermaterial. In some embodiments, first IMD layer 104 comprises first IMDlayers 104 a, 104 b, 104 c, and 104 d. LC structure 100 includes a firstconductive line 106 a in first IMD layer 104 a. The first conductiveline 106 a and first IMD layer 104 a are over the first substrate 102.LC structure 100 includes a first IMD layer 104 b over the firstconductive line 106 a and a first shielding layer 114 in first IMD layer104 b. The first shielding layer 114 is over the first conductive line106 a. LC structure 100 includes a first IMD layer 104 c over the firstshielding layer 114 and a first gate layer 118 in first IMD layer 104 c.The first gate layer 118 is over the first shielding layer 114. LCstructure 100 includes a first recess portion 116 which connects firstIMD layer 104 b and first IMD layer 104 c. In some embodiments, thefirst shielding layer 114 is separated from a conductive line 140 by thefirst recess portion 116. LC structure 100 includes first IMD layer 104d over the first gate layer 118 and a second substrate 120 over firstIMD layer 104 d.

LC structure 100 includes a second substrate 120 over first substrate102 and first IMD layer 104. LC structure 100 includes a second IMDlayer 126 over the second substrate 120. A second conductive line 106 b,a second shielding layer 130 and a second gate layer 128 are in secondIMD layer 126. In some embodiments, second IMD layer 126 is amulti-layer material. In some embodiments, second IMD layer 126comprises second IMD layers 126 a, 126 b, 126 c, and 126 d. LC structure100 includes a second gate layer 128 in second IMD layer 126 a. Thesecond gate layer 128 and second IMD layer 126 a are over the secondsubstrate 120. LC structure 100 includes a second IMD layer 126 b overthe second gate layer 128 and a second shielding layer 130 in second IMDlayer 126 b. The second shielding layer 130 is over the second gatelayer 128. LC structure 100 includes a second IMD layer 126 c over thesecond shielding layer 130 and a second conductive line 106 b in secondIMD layer 126 c. The second conductive line 106 b is over the secondshielding layer 130. LC structure 100 includes a second recess portion132 which connects second IMD layer 126 b and second IMD layer 126 c. Insome embodiments, the second shielding layer 130 is separated from theconductive line 140 by the second recess portion 132. LC structure 100includes a second IMD layer 126 d over the second conductive line 106 b.In some embodiments, the second IMD layer 126 d is omitted. Conductiveline 140 electrically connects first conductive line 106 a and secondconductive line 106 b through second substrate 120. A switch 122 isformed in second substrate 120 to selectively connect different portionsof first conductive line 106 a and second conductive line 106 b. Aninsulator 124 is formed in second substrate 120 to electrically isolateconductive line 140 from second substrate 120. In some embodiments,insulator 124 includes a dielectric material including oxide or anothersuitable insulating material.

In some embodiments, first substrate 102 includes an elementalsemiconductor including silicon or germanium in crystal,polycrystalline, or an amorphous structure; a compound semiconductorincluding silicon carbide, gallium arsenic, gallium phosphide, indiumphosphide, indium arsenide, and indium antimonide; an alloysemiconductor including SiGe, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, andGaInAsP; any other suitable material; or combinations thereof. In someembodiments, the alloy semiconductor substrate has a gradient SiGefeature in which the Si and Ge composition change from one ratio at onelocation to another ratio at another location of the gradient SiGefeature. In some embodiments, the alloy SiGe is formed over a siliconsubstrate. In some embodiments, first substrate 102 is a strained SiGesubstrate. In some embodiments, the semiconductor substrate has asemiconductor on insulator structure, such as a silicon on insulator(SOD structure. In some embodiments, the semiconductor substrateincludes a doped epi layer or a buried layer. In some embodiments, thecompound semiconductor substrate has a multilayer structure, or thesubstrate includes a multilayer compound semiconductor structure. Insome embodiments, a thickness of first substrate ranges from about 30microns (μm) to about 50 μm.

In some embodiments, first IMD layer 104 is a multi-layer materialhaving conductive lines extending in a plane parallel to a top surfaceof first substrate 102 in each layer and conductive vias connectingconductive lines on separate layers in the first IMD layer. First IMDlayer 104 includes a dielectric material configured to insulate theconductive lines or conductive vias. In some embodiments, first IMDlayer 104 includes an interconnect structure configured to electricallyconnect active devices in or on first substrate 102. In someembodiments, the dielectric material of first IMD layer 102 includes alow-k dielectric material. A low-k dielectric material has a dielectricconstant less than that of silicon dioxide. In some embodiments, firstIMD layer 104 comprises a plurality of layers. In some embodiments,first IMD layer 104 comprises first IMD layers 104 a, 104 b, 104 c, and104 d. In some embodiments, first IMD layer 104 includes a dielectricmaterial including oxide or another suitable insulating material.

First conductive line 106 a includes conductive lines in first IMD layer104. In some embodiments, first conductive line 106 a is in atwo-dimensional plane in first IMD layer 104. In some embodiments, firstconductive line 106 a is positioned in a two-dimensional plane which isparallel to first shielding layer 114. In some embodiments, firstconductive line 106 a is a three-dimensional structure in first IMDlayer 104. The three-dimensional structure includes a combination ofconductive lines on different layers of first IMD layer 104 andconductive vias connecting the conductive lines. First conductive line106 a includes a first straight conductive line 112 a and a secondstraight conductive line 112 b on a same level of first IMD layer 104.First conductive line 106 a further includes a third straight conductiveline 108 on a different level of first IMD layer 104. First conductiveline 106 a further includes a first conductive via 110 a connectingfirst straight conductive line 112 a to third straight conductive line108; and a second conductive via 110 b connecting second straightconductive line 112 b to third straight conductive line 108. In someembodiments, first straight conductive line 112 a and second straightconductive line 112 b are on a level of first IMD layer 104 above thirdstraight conductive line 108. In some embodiments, first straightconductive line 112 a and second straight conductive line 112 b are on alevel of first IMD layer 104 below third straight conductive line 108.In some embodiments, first conductive line 106 a includes a single portfor either receiving or outputting an electrical current. In someembodiments, first conductive line 106 a includes more than one port andis capable of both receiving and outputting an electrical current. Insome embodiments, first conductive line 106 a includes copper, aluminum,nickel, tungsten, titanium, or another suitable conductive material. Insome embodiments, first conductive line is omitted and LC structure 100includes only second conductive line 106 b. In some embodiments, athickness of first conductive line 106 a ranges from about 0.1 μm toabout 4 μm. In some embodiments, a depth of first straight conductiveline 112 a ranges from about 0.1 μm to about 4 μm. In some embodiments,first conductive line 106 a includes one or more inductors with a rangeof inductances from about 0.5 (nanohenries) nH to about 10 nH.

In some embodiments, first conductive line 106 a is a meandering typeconductive winding in which a conductive line extends along an angleddirection with respect to an x-axis and a y-axis of first IMD layer 104.Conductive lines in a same layer of first IMD layer 104 extend parallelto one another. Conductive lines in a different layer of first IMD layer104 are arranged to allow electrical connection between the parallelconductive lines; and conductive vias connect the conductive lines onthe different layers of the first IMD layer 104.

In some embodiments, first conductive line 106 a is a spiral typeconductive winding in which conductive lines are arranged in a spiralarrangement in different layers of first IMD layer 104. Conductive viasprovide electrical connections between the conductive lines in thedifferent layers of first IMD layer 104.

First shielding layer 114 includes a conductive material to isolatefirst conductive line 106 a and second conductive line 106 b. Firstshielding layer 114 reduces the mutual inductive coupling and capacitivecoupling between first conductive line 106 a and second conductive line106 b. In some embodiments, first shielding layer 114 is in atwo-dimensional plane in first IMD layer 104. In some embodiments, firstshielding layer 114 is a three-dimensional structure in first IMD layer104. In some embodiments, the orientation of the first shielding layer114 is parallel to the first conductive line 106 a and second conductiveline 106 b. In some embodiments, the first shielding layer 114 includesa conductive plate coupled to ground. In some embodiments, the firstshielding layer 114 is a solid conductor with a plate-like shape. Insome embodiments, the first shielding layer 114 includes a solidconductor with hole-like portions, formed therein, shaped in variouspatterns, such as rectangular, square, circular, hexagonal, or othergeometric shapes.

First shielding layer 114 is electrically isolated from the conductiveline 140 by the first recess portion 116. First recess portion 116 has awidth between about 4 μm and about 30 μm. First shielding layer 114 hasa thickness between about 0.1 μm and about 2 μm. In some embodiments,the thickness of the first shielding layer 114 is larger or smallerdepending on design requirements for the LC structure 100. A largerthickness will provide greater protection from mutual inductive couplingand capacitive coupling. A smaller thickness will reduce the protectionfrom mutual inductive coupling and capacitive coupling. In someembodiments, first shielding layer 114 includes copper, aluminum,nickel, tungsten, titanium, or another suitable conductive material. Insome embodiments, first shielding layer 114 is omitted and LC structure100 includes only second shielding layer 130. In some embodiments, firstshielding layer 114 provides a range of attenuation from −0.1 dB to 2 dBover a range of frequencies from 10 gigahertz (GHz) to 30 GHz.

Capacitor C1 is the effective capacitance between the first shieldinglayer 114 and the first gate layer 118. In some embodiments, capacitorC1 is referred to as a Metal Oxide Metal Capacitor (MOMCAP). In someembodiments, the value of capacitor C1 is fixed. Capacitor C1 has acapacitance between about 30 femtofarads (fF) and about 3 picofarads(pF).

First gate layer 118 is formed in first IMD layer 104. First gate layer118 is electrically connected to second gate layer 128 by conductiveline 140. First gate layer 118 is a gate electrode where a first inputsignal to the lower portion of LC structure 100 is applied. First gatelayer 118 includes a doped or non-doped polycrystalline silicon (orpolysilicon). Alternatively, the first gate layer 118 includes a metal,such as Al, Cu, W, Ti, Ta, TiN, TaN, NiSi, CoSi, other suitableconductive materials, or combinations thereof, in some embodiments. Insome embodiments, the first gate layer 118 is formed by chemical vapordeposition (CVD), physical vapor deposition (PVD), atomic layerdeposition (ALD), plating, or other processes. In some embodiments, thefirst gate layer 118 has a multilayer structure and is formed in amultiple-step process. In some embodiments, first gate layer 118 isomitted and LC structure 100 includes only second gate layer 128.

First gate layer 118 has a thickness between about 0.1 μm and about 2μm. In some embodiments, the thickness of the first gate layer 118 islarger or smaller depending on design requirements for the LC structure100.

Capacitor C2 is the effective capacitance between the first gate layer118 and the second substrate 120. In some embodiments, capacitor C2 isreferred to as a Metal Oxide Substrate Capacitor (MOSCAP). The value ofcapacitor C2 is tunable based on a voltage of first input signal appliedto the first gate layer 118. In some embodiments, the capacitance valueof capacitor C2 is increased as the voltage applied to the first gatelayer 118 is increased. In some embodiments, the capacitance value ofcapacitor C2 is decreased as the voltage applied to the first gate layer118 is decreased. In some embodiments, the value of capacitor C2 isadjusted to tune the first LC tank circuit 100 a of LC structure 100.Capacitor C2 has a capacitance between about 30 fF and about 3 pF.

Second substrate 120 is above first IMD layer 104 and first gate layer118. Second substrate 120 is used to create a 3-Dimensional IntegratedCircuit (3-D IC). In some embodiments, second substrate 120 is used tocreate a symmetric circuit structure positioned above and below thesecond substrate 120. In some embodiments, second substrate 120 is usedto create a stacked, differential LC tank circuit structure whichincludes a first LC tank circuit structure located above the secondsubstrate 120 and outputs a signal 180 degrees out of phase with anoutput of a second LC tank circuit structure positioned below the secondsubstrate 120. In some embodiments, second substrate 120 is used tocreate asymmetric circuit structures positioned above and below thesecond substrate 120. In some embodiments, second substrate 120 isconnected to ground (not shown). In some embodiments, second substrate120 includes polysilicon, doped silicon, or other suitable conductivematerials. In some embodiments, a thickness of second substrate 120ranges from about 50 nanometers (nm) to about 150 nm. In someembodiments, the thickness of second substrate 120 ranges from about 150nanometers (nm) to about 450 nm. In some embodiments, the thickness ofsecond substrate 120 ranges from about 450 nanometers (nm) to about 850nm. If the thickness of second substrate 120 is too great, formingconductive line 140 becomes difficult and the length of the conductiveline 140 unnecessarily increases resistance in LC structure 100, in someembodiments.

In some embodiments, a separation between first conductive line 106 aand second substrate 120 ranges from about 500 nm to about 1 μm. In someembodiments, the separation between first conductive line 106 a andsecond substrate 120 ranges from about 1 μm to about 2 μm. In someembodiments, the separation between first conductive line 106 a andsecond substrate 120 ranges from about 2 μm to about 5 μm. In someembodiments, the separation between first conductive line 106 a andsecond substrate 120 ranges from about 5 μm to about 15 μm. If theseparation is too small, first IMD layer 104 is not able to providesufficient insulation between first conductive line 106 a and secondsubstrate 120, in some embodiments.

Second IMD layer 126 includes a dielectric material configured toinsulate the conductive lines or conductive vias. In some embodiments,second IMD layer 126 is a multi-layer material having conductive linesextending in a plane parallel to a top surface of second substrate 120.In some embodiments, second IMD layer 126 is a multi-layer materialhaving one or more conductive lines positioned in each layer of secondIMD layer 126. In some embodiments, second IMD layer 126 is amulti-layer material having conductive vias connecting conductive linesin separate layers of the second IMD layer 126. In some embodiments,second IMD layer 126 includes an interconnect structure configured toelectrically connect active devices in second substrate 120. Thedielectric material in second IMD layer 126 is used to provideinsulation between adjacent conductive lines or conductive vias. In someembodiments, the dielectric material of second IMD layer 126 includes alow-k dielectric material. In some embodiments, the dielectric materialof second IMD layer 126 is a same dielectric material as first IMD layer104. In some embodiments, the dielectric material of second IMD layer126 is different from the dielectric material of first IMD layer 104. Insome embodiments, second IMD layer 126 comprises a plurality of layers.In some embodiments, second IMD layer 126 comprises second IMD layers126 a, 126 b, 126 c, and 126 d. In some embodiments, second IMD layer126 includes a dielectric material including oxide or another suitableinsulating material.

In some embodiments, a separation between second conductive line 106 band second substrate 120 ranges from about 1 μm to about 2 μm. In someembodiments, the separation between second conductive line 106 b andsecond substrate 120 ranges from about 2 μm to about 5 μm. In someembodiments, the separation between second conductive line 106 b andsecond substrate 120 ranges from about 5 μm to about 15 μm. If theseparation is too small, second IMD layer 126 is not able to providesufficient insulation between second conductive line 106 b and secondsubstrate 120, in some embodiments. In some embodiments, the separationbetween first conductive line 106 a and second substrate 120 is equal tothe separation between second conductive line 106 b and the secondsubstrate. In some embodiments, the separation between first conductiveline 106 a and second substrate 120 is different from the separationbetween second conductive line 106 b and the second substrate.

Second gate layer 128 is in second IMD layer 126. Second gate layer 128is electrically connected to first gate layer 118 by conductive line140. Second gate layer 128 is a gate electrode where a second inputsignal to the upper portion of LC structure 100 is applied. Second gatelayer 128 includes a doped or non-doped polycrystalline silicon (orpolysilicon). Alternatively, the second gate layer 128 includes a metal,such as Al, Cu, W, Ti, Ta, TiN, TaN, NiSi, CoSi, other suitableconductive materials, or combinations thereof, in some embodiments. Insome embodiments, the second gate layer 128 is formed by CVD, PVD, ALD,plating, or other processes. In some embodiments, the second gate layer128 has a multilayer structure and is formed in a multiple-step process.In some embodiments, second gate layer 128 is omitted and LC structure100 includes only first gate layer 118.

Second gate layer 128 has a thickness between about 0.1 μm and about 2μm. In some embodiments, the thickness of the second gate layer 128 islarger or smaller depending on design requirements for the LC structure100.

Capacitor C3 is the effective capacitance between the second gate layer128 and the second substrate 120. In some embodiments, capacitor C3 isreferred to as a MOSCAP. The value of capacitor C3 is tunable based on avoltage of second input signal applied to the second gate layer 128. Insome embodiments, the capacitance value of capacitor C3 is increased asthe voltage applied to the second gate layer 128 is increased. In someembodiments, the capacitance value of capacitor C3 is decreased as thevoltage applied to the second gate layer 128 is decreased. In someembodiments, the value of capacitor C3 is adjusted to tune the second LCtank circuit 300 b of LC structure 100. Capacitor C3 has a capacitancebetween about 30 fF and about 3 pF.

Second shielding layer 130 includes a conductive material to isolatefirst conductive line 106 a and second conductive line 106 b. Secondshielding layer 130 reduces the mutual inductive coupling and capacitivecoupling between first conductive line 106 a and second conductive line106 b. In some embodiments, second shielding layer 130 is in atwo-dimensional plane in second IMD layer 126. In some embodiments,second shielding layer 130 is a three-dimensional structure in secondIMD layer 126. In some embodiments, the orientation of the secondshielding layer 130 is parallel to the first conductive line 106 a andsecond conductive line 106 b. In some embodiments, the second shieldinglayer 130 includes a conductive plate coupled to ground. In someembodiments, the second shielding layer 130 is a solid conductor with aplate-like shape. In some embodiments, the second shielding layer 130includes a solid conductor with hole-like portions, formed therein,shaped in various patterns, such as rectangular, square, circular,hexagonal, or other geometric shapes.

Second shielding layer 130 is electrically isolated from the conductiveline 140 by the second recess portion 132. Second recess portion 132 hasa width between about 0.1 μm and about 5 μm. Second shielding layer 130has a thickness between about 0.1 μm and about 4 μm. In someembodiments, the thickness of the second shielding layer 130 is largeror smaller depending on design requirements for the LC structure 100. Alarger thickness will provide greater protection from mutual inductivecoupling and capacitive coupling. A smaller thickness will reduce theprotection from mutual inductive coupling and capacitive coupling. Oneof ordinary skill in the art will recognize the ability to select adesired thickness attuned to the design requirements of the LC structure100. In some embodiments, second shielding layer 130 includes copper,aluminum, nickel, tungsten, titanium, or another suitable conductivematerial. In some embodiments, second shielding layer 130 is omitted andLC structure 100 includes only first shielding layer 114. In someembodiments, second shielding layer 134 provides a range of attenuationfrom 0.1 dB to 2 dB over a range of frequencies from 10 GHz to 30 GHz.

Capacitor C4 is the effective capacitance between the second gate layer128 and the second shielding layer 130. In some embodiments, capacitorC4 is referred to as a MOMCAP. In some embodiments, the value ofcapacitor C4 is fixed. Capacitor C4 has a capacitance between about 30fF and about 3 pF.

Second conductive line 106 b includes conductive lines in second IMDlayer 126. In some embodiments, second conductive line 106 b is aconductive winding structure in a two-dimensional plane in second IMDlayer 126. In some embodiments, second conductive line 106 b ispositioned in a two-dimensional plane which is parallel to secondshielding layer 130. In some embodiments, second conductive line 106 bis a three-dimensional conductive winding structure in second IMD layer126. In some embodiments, second conductive line 106 b includes a singleport for either receiving or outputting an electrical current. Secondconductive line 106 b includes a first straight conductive line 138 aand a second straight conductive line 138 b on a same level of secondIMD layer 126. Second conductive line 106 b further includes a thirdstraight conductive line 134 on a different level of second IMD layer126. Second conductive line 106 b further includes a first conductivevia 136 a connecting first straight conductive line 138 a to thirdstraight conductive line 134; and a second conductive via 136 bconnecting second straight conductive line 138 b to third straightconductive line 134. In some embodiments, first straight conductive line138 a and second straight conductive line 138 b are on a level of secondIMD layer 126 above third straight conductive line 134. In someembodiments, first straight conductive line 138 a and second straightconductive line 138 b are on a level of second IMD layer 126 below thirdstraight conductive line 134. In some embodiments, second conductiveline 106 b includes more than one port and is capable of both receivingand outputting an electrical current. In some embodiments, secondconductive line 106 b includes copper, aluminum, nickel, tungsten,titanium, or another suitable conductive material. In some embodiments,second conductive line 106 b is omitted and LC structure 100 includesfirst conductive line 106 a. In some embodiments, a shape of secondconductive line 106 b is a same shape as first conductive line 106 a. Insome embodiments, the shape of second conductive line 106 b is differentfrom first conductive line 106 a. In some embodiments, a thickness ofsecond conductive line 106 b ranges from about 0.1 μm to about 4 μm. Insome embodiments, a depth of second straight conductive line 138 aranges from about 0.5 μm to about 4 μm. In some embodiments, secondconductive line 106 b includes one or more inductors with a range ofinductances from about 0.5 nH to about 10 nH.

In some embodiments, second conductive line 106 b is a meandering typeconductive winding in which a conductive line extends along an angleddirection with respect to an x-axis and a y-axis of second IMD layer126. Conductive lines in a same layer of second IMD layer 126 extendparallel to one another. Conductive lines in a different layer of secondIMD layer 126 are arranged to allow electrical connection between theparallel conductive lines; and conductive vias connect the conductivelines on the different layers of the second IMD layer 126.

In some embodiments, second conductive line 106 b is a spiral typeconductive winding in which conductive lines are arranged in a spiralarrangement in different layers of second IMD layer 126. Conductive viasprovide electrical connections between the conductive lines in thedifferent layers of second IMD layer 126.

Conductive line 140 is used to electrically connect first conductiveline 106 a to second conductive line 106 b. Conductive line 140 extendsthrough second substrate 120. In some embodiments, conductive line 140is a metal line, a via, a through silicon via (TSV), an inter-level via(ILV), or another suitable conductive line. In some embodiments,conductive line 140 includes copper, aluminum, nickel, titanium,tungsten or another suitable conductive material. In some embodiments,conductive line 140 is a same material as first conductive line 106 aand second conductive line 106 b. In some embodiments, conductive line140 is a different material from first conductive line 106 a or secondconductive material 106 b. In some embodiments, conductive line 140 isomitted to prevent direct electrical connection between first conductiveline 106 a and second conductive line 106 b. Conductive line 140 is usedto electrically connect first gate layer 118 and second gate layer 128.In some embodiments, conductive line 140 includes one or more conductiveline portions.

Switch 122 is formed in second substrate 120 to selectively connectdifferent portions of first conductive line 106 a and second conductiveline 106 b. In some embodiments, switch 122 includes a plurality oftransistors, such as metal-oxide-semiconductor (MOS) transistors,bi-polar junction transistors (BJTs), high electron mobility transistors(HEMTs), or other suitable switching elements. By independentlyactivating switch 122, an inductance and Q factor of LC structure 100 isadjustable. In some embodiments, switch 122 is activated based oncontrol signals received from a controller. In some embodiments, thecontrol signals are generated in response to a user input. In someembodiments, the control signals are generated automatically in responseto a detected current change. In some embodiments, in which switch 122includes transistors, the control signal is applied to a gate of theswitch 122 to selectively activate the switch 122. In some embodiments,switch 122 allows LC structure 100 to operate in a dual frequency banddesign. In some embodiments, switch 122 allows LC structure 100 tooperate at 2.4 GHz and 5.8 GHz.

FIG. 1B is a perspective view of an LC structure 100′ in accordance withone or more embodiments. LC structure 100′ is an embodiment of LCstructure 100 with similar elements. As shown in FIG. 1B, similarelements have a same reference number as shown in FIG. 1A. LC structure100′ is an embodiment of LC structure 100 without substrate 102, firstIMD layer 104 and second IMD layer 126 (for illustrative purposes).

FIG. 2A is a cross sectional view of an LC structure 200 in accordancewith one or more embodiments. LC structure 200 is an embodiment of LCstructure 100 (shown in FIG. 1A) with similar elements. As shown in FIG.2A, similar elements have a same reference number as shown in FIG. 1Aincreased by 100. LC structure 200 includes second conductive line 206b, second shielding layer 230 and second gate layer 228 in second IMDlayer 226. LC structure 200 includes conductive line 240 a. Conductiveline 240 a is an embodiment of conductive line 140 shown in FIG. 1A.Conductive line 240 a is used to electrically connect second conductiveline 206 b to second gate layer 228. In some embodiments, conductiveline 240 a extends into substrate 220 providing additional capacitanceto LC structure 200.

FIG. 2B is a cross sectional view of an LC structure 200′ in accordancewith one or more embodiments. LC structure 200′ is an embodiment of LCstructure 100 (shown in FIG. 1A) with similar elements. As shown in FIG.2B, similar elements have a same reference number as shown in FIG. 1Aincreased by 100. In comparison with LC structure 200 (shown in FIG.2A), LC structure 200′ does not include a second conductive line 206 b,second shielding layer 230 and second gate layer 228 in a second IMDlayer 226. LC structure 200′ includes first conductive line 206 a, firstshielding layer 214 and first gate layer 218 in first IMD layer 204. LCstructure 200′ includes conductive line 240 b. Conductive line 240 b isan embodiment of conductive line 140 shown in FIG. 1A. Conductive line240 b is used to electrically connect first conductive line 206 a tofirst gate layer 218. In some embodiments, conductive line 240 b extendsinto substrate 220 providing additional capacitance to LC structure200′.

FIG. 3A is a cross sectional view of an LC transmission line structure300 in accordance with one or more embodiments. LC transmission linestructure 300 is an embodiment of LC structure 100 (shown in FIG. 1A)with similar elements. As shown in FIG. 3, similar elements have a samereference number as shown in FIG. 1A increased by 200. LC transmissionline structure 300 includes first conductive line 306 a and secondconductive line 306 b. In comparison with LC structure 100 (shown inFIG. 1A), first conductive line 306 a does not include first straightconductive line 112 a, second straight conductive line 112 b, thirdstraight conductive line 108, first conductive via 110 a, and secondconductive via 110 b. In comparison with LC structure 100 (shown in FIG.1A), second conductive line 306 b does not include first straightconductive line 138 a, second straight conductive line 138 b, thirdstraight conductive line 134, first conductive via 136 a, and secondconductive via 136 b. In some embodiments, LC transmission linestructure 300 is in a stacked configuration with a first LC transmissionline structure 300 a located below the second substrate 320, and asecond LC transmission line structure 300 b located above the secondsubstrate 320. In some embodiments, first LC transmission line structure300 a and second LC transmission line structure 300 b operate in adifferential mode.

First conductive line 306 a includes lower conductive line 312 in firstIMD layer 304. In some embodiments, first conductive line 306 a includesone or more lower conductive lines in first IMD layer 304. In someembodiments, lower conductive line 312 is a transmission line structure.In some embodiments, lower conductive line 312 is a conductive structurein a two-dimensional plane in first IMD layer 304. In some embodiments,lower conductive line 312 is a three-dimensional conductive structure infirst IMD layer 304. In some embodiments, lower conductive line 312 isparallel to first shielding layer 314. In some embodiments, lowerconductive line 312 includes a single port for either receiving oroutputting an electrical current. In some embodiments, lower conductiveline 312 includes more than one port and is capable of both receivingand outputting an electrical current. In some embodiments, lowerconductive line 312 is capable of both receiving and outputting anelectrical signal with a frequency range of about 10 GHz to about 30GHz. In some embodiments, lower conductive line 312 includes copper,aluminum, nickel, tungsten, titanium, or another suitable conductivematerial. In some embodiments, lower conductive line 312 is omitted andLC transmission line structure 300 includes upper conductive line 338.In some embodiments, a shape of lower conductive line 312 is a sameshape as upper conductive line 338. In some embodiments, the shape oflower conductive line 312 is different from upper conductive line 338.In some embodiments, a thickness of lower conductive line 312 rangesfrom about 0.1 μm to about 4 μm. In some embodiments, a depth of lowerconductive line 312 ranges from about 0.1 μm to about 4 μm.

Second conductive line 306 b includes upper conductive line 338 insecond IMD layer 326. In some embodiments, second conductive line 306 bincludes one or more upper conductive lines in second IMD layer 326. Insome embodiments, upper conductive line 338 is a transmission linestructure. In some embodiments, upper conductive line 338 is aconductive structure in a two-dimensional plane in second IMD layer 326.In some embodiments, upper conductive line 338 is a three-dimensionalconductive structure in second IMD layer 326. In some embodiments, upperconductive line 338 is parallel to second shielding layer 330. In someembodiments, upper conductive line 338 includes a single port for eitherreceiving or outputting an electrical current. In some embodiments,upper conductive line 338 includes more than one port and is capable ofboth receiving and outputting an electrical current. In someembodiments, upper conductive line 338 is capable of both receiving andoutputting an electrical signal with a frequency range of about 10gigahertz (GHz) to about 30 GHz. In some embodiments, upper conductiveline 338 includes copper, aluminum, nickel, tungsten, titanium, oranother suitable conductive material. In some embodiments, upperconductive line 338 is omitted and LC transmission line structure 300includes only lower conductive line 312. In some embodiments, a shape ofupper conductive line 338 is a same shape as lower conductive line 312.In some embodiments, the shape of upper conductive line 338 is differentfrom lower conductive line 312. In some embodiments, a thickness ofupper conductive line 338 ranges from about 0.1 μm to about 4 μm. Insome embodiments, a depth of upper conductive line 338 ranges from about0.1 μm to about 4 μm.

In some embodiments, first conductive line 306 a and second conductive306 b are meandering type conductive line(s) in which a conductive lineextends along an angled direction with respect to an x-axis and a y-axisof second IMD layer 326. In some embodiments, conductive lines in a samelayer of second IMD layer 326 extend parallel to one another. In someembodiments, conductive lines in a same layer of second IMD layer 326extend perpendicular to one another.

In some embodiments, a separation between first conductive line 306 aand second substrate 320 ranges from about 0.2 μm to about 2 μm. In someembodiments, a separation between second conductive line 306 b andsecond substrate 320 ranges from about 0.2 μm to about 2 μm. In someembodiments, the separation between second conductive line 306 b andsecond substrate 320 is equal to the separation between first conductiveline 306 a and the second substrate 320. In some embodiments, theseparation between second conductive line 306 b and second substrate 320is different from the separation between first conductive line 306 a andthe second substrate 320.

FIG. 3B is a perspective view of an LC transmission line structure 300′in accordance with one or more embodiments. LC transmission linestructure 300′ is an embodiment of LC structure 300 with similarelements. As shown in FIG. 3B, similar elements have a same referencenumber as shown in FIG. 3A. LC transmission line structure 300′ is anembodiment of LC transmission line structure 300 without substrate 302,first IMD layer 304 and second IMD layer 326 (for illustrativepurposes).

FIG. 4A is a cross sectional view of an LC transmission line structure400 in accordance with one or more embodiments. LC transmission linestructure 400 is an embodiment of LC transmission line structure 300(shown in FIG. 3A) with similar elements. As shown in FIG. 4A, similarelements have a same reference number as shown in FIG. 3A increased by100. LC transmission line structure 400 includes second conductive line406 b, upper conductive line 438, second shielding layer 430 and secondgate layer 428 in second IMD layer 426. LC transmission line structure400 includes conductive line 440 a. Conductive line 440 a is anembodiment of conductive line 340 shown in FIGS. 3A & 3B. Conductiveline 440 a is used to electrically connect second conductive line 406 bto second gate layer 428. In some embodiments, conductive line 440 aextends into substrate 420 providing additional capacitance to LCstructure 400.

FIG. 4B is a cross sectional view of an LC transmission line structure400′ in accordance with one or more embodiments. LC transmission linestructure 400′ is an embodiment of LC transmission line structure 300(shown in FIG. 3A) with similar elements. As shown in FIG. 4B, similarelements have a same reference number as shown in FIG. 3A increased by100. In comparison with LC transmission line structure 400 (shown inFIG. 4A), LC structure 400′ does not include a second conductive line406 b, upper conductive line 438, second shielding layer 430 and secondgate layer 428 in a second IMD layer 426. LC transmission line structure400′ includes first conductive line 406 a, lower conductive line 412,first shielding layer 414 and first gate layer 418 in first IMD layer404. LC structure 400′ includes conductive line 440 b. Conductive line440 b is an embodiment of conductive line 340 shown in FIG. 3.Conductive line 440 b is used to electrically connect first conductiveline 406 a to first gate layer 418. In some embodiments, conductive line440 b extends into substrate 420 providing additional capacitance to LCstructure 400′.

FIG. 5 is a cross sectional view of an LC structure 500 in accordancewith one or more embodiments. LC structure 500 is an embodiment of LCstructure 100 (shown in FIG. 1A) with similar elements. As shown in FIG.5, similar elements have a same reference number as shown in FIG. 1Aincreased by 400. In comparison with LC structure 100 (shown in FIG.1A), LC structure 500 does not include first gate layer 118 and secondgate layer 128.

In some embodiments, LC structure 500 is in a stacked configuration witha first LC tank circuit structure 500 a located below the secondsubstrate 520, and a second LC tank circuit structure 500 b locatedabove the second substrate 520. In some embodiments, first LC tankcircuit structure 500 a and second LC tank circuit structure 500 boperate in a differential mode.

LC structure 500 includes a first shielding layer 514 over the firstconductive line 506 a. LC structure 500 includes a first IMD layer 504 cover the first shielding layer 514. LC structure 500 includes a secondsubstrate 520 over first IMD layer 504 c. LC structure 500 includes asecond IMD layer 526 a over the second substrate 520 and a secondshielding layer 530 in second IMD layer 526 a. LC structure 500 includesa second IMD layer 526 c over the second shielding layer 530 and asecond conductive line 506 b in second IMD layer 526 c. The secondconductive line 506 b is over the second shielding layer 530. LCstructure 500 includes a second IMD layer 526 d over the secondconductive line 506 b. In some embodiments, the second IMD layer 526 dis omitted.

Capacitor C5 is the effective capacitance between the first shieldinglayer 514 and the second substrate 520. In some embodiments, capacitorC5 is referred to as a MOSCAP. The value of capacitor C5 is tunablebased on a voltage of first input signal applied to the first conductiveline 506 a. In some embodiments, the capacitance value of capacitor C5is increased as the voltage applied to the first conductive line 506 ais increased. In some embodiments, the capacitance value of capacitor C5is decreased as the voltage applied to the first conductive line 506 ais decreased. In some embodiments, the value of capacitor C5 is adjustedto tune the first LC tank circuit 500 a of LC structure 500. CapacitorC5 has a capacitance between about 30 fF and about 3 pF.

Capacitor C6 is the effective capacitance between the second shieldinglayer 530 and the second substrate 520. In some embodiments, capacitorC6 is referred to as a MOSCAP. The value of capacitor C6 is tunablebased on a voltage of a second input signal applied to the secondconductive line 506 b. In some embodiments, the capacitance value ofcapacitor C6 is increased as the voltage applied to the secondconductive line 506 b is increased. In some embodiments, the capacitancevalue of capacitor C6 is decreased as the voltage applied to the secondconductive line 506 b is decreased. In some embodiments, the value ofcapacitor C6 is adjusted to tune the second LC tank circuit 500 b of LCstructure 500. Capacitor C6 has a capacitance between about 30 fF andabout 3 pF.

FIG. 6A is a cross sectional view of an LC structure 600 in accordancewith one or more embodiments. LC structure 600 is an embodiment of LCstructure 500 (shown in FIG. 5) with similar elements. As shown in FIG.6A, similar elements have a same reference number as shown in FIG. 5increased by 100. LC structure 600 includes second conductive line 606 band second shielding layer 630 in second IMD layer 626. LC structure 600includes conductive line 640 a. Conductive line 640 a is an embodimentof conductive line 540 shown in FIG. 5. In some embodiments, insulator624 is used to electrically isolate conductive line 640 a from substrate620. In some embodiments, substrate 620 is connected to ground.

FIG. 6B is a cross sectional view of an LC structure 600′ in accordancewith one or more embodiments. LC structure 600′ is an embodiment of LCstructure 500 (shown in FIG. 5) with similar elements. As shown in FIG.6B, similar elements have a same reference number as shown in FIG. 5increased by 100. In comparison with LC structure 500 (shown in FIG. 5),LC structure 600′ does not include a second conductive line 606 b andsecond shielding layer 630 in second IMD layer 626. LC structure 600′includes first conductive line 606 a and first shielding layer 614 infirst IMD layer 604. LC structure 600′ includes conductive line 640 b.Conductive line 640 b is an embodiment of conductive line 540 shown inFIG. 5. In some embodiments, insulator 624 is used to electricallyisolate conductive line 640 b from substrate 620. In some embodiments,substrate 620 is connected to ground.

FIG. 7 is a cross sectional view of an LC transmission line structure700 in accordance with one or more embodiments. LC transmission linestructure 700 is an embodiment of LC structure 500 (shown in FIG. 5)with similar elements. As shown in FIG. 7, similar elements have a samereference number as shown in FIG. 5 increased by 200. LC transmissionline structure 700 includes first conductive line 706 a and secondconductive line 706 b. In comparison with LC structure 500 (shown inFIG. 5), first conductive line 706 a does not include first straightconductive line 512 a, second straight conductive line 512 b, thirdstraight conductive line 508, first conductive via 510 a, and secondconductive via 510 b. In comparison with LC structure 500 (shown in FIG.5), second conductive line 706 b does not include first straightconductive line 538 a, second straight conductive line 538 b, thirdstraight conductive line 534, first conductive via 536 a, and secondconductive via 536 b. In some embodiments, LC transmission linestructure 700 is in a stacked configuration with a first LC transmissionline structure 700 a located below the second substrate 720, and asecond LC transmission line structure 700 b located above the secondsubstrate 720. In some embodiments, first LC transmission line structure700 a and second LC transmission line structure 700 b operate in adifferential mode.

First conductive line 706 a includes lower conductive line 712 in firstIMD layer 704. First conductive line 706 a is an embodiment of firstconductive line 306 a shown in FIG. 3A. Lower conductive line 712 is anembodiment of lower conductive line 312 shown in FIG. 3A. Secondconductive line 706 b includes upper conductive line 738 in second IMDlayer 726. Second conductive line 706 b is an embodiment of secondconductive line 306 b shown in FIG. 3B. Upper conductive line 738 is anembodiment of upper conductive line 338 shown in FIG. 3B.

FIG. 8A is a cross sectional view of an LC structure 800 in accordancewith one or more embodiments. LC structure 800 is an embodiment of LCstructure 600 (shown in FIG. 6) with similar elements. As shown in FIG.8A, similar elements have a same reference number as shown in FIG. 7increased by 100. LC structure 800 includes second conductive line 806 band second shielding layer 830 in second IMD layer 826. LC structure 800includes conductive line 840 a. Conductive line 840 a is an embodimentof conductive line 740 shown in FIG. 7. In some embodiments, insulator824 is used to electrically isolate conductive line 840 a from substrate820. In some embodiments, substrate 820 is connected to ground.

FIG. 8B is a cross sectional view of an LC structure 800′ in accordancewith one or more embodiments. LC structure 800′ is an embodiment of LCstructure 700 (shown in FIG. 7) with similar elements. As shown in FIG.8B, similar elements have a same reference number as shown in FIG. 7increased by 100. In comparison with LC structure 700 (shown in FIG. 7),LC structure 800′ does not include a second conductive line 806 b andsecond shielding layer 830 in second IMD layer 826. LC structure 800′includes first conductive line 806 a and first shielding layer 814 infirst IMD layer 804. LC structure 800′ includes conductive line 840 b.Conductive line 840 b is an embodiment of conductive line 740 shown inFIG. 7. In some embodiments, insulator 824 is used to electricallyisolate conductive line 840 b from substrate 820. In some embodiments,substrate 820 is connected to ground.

FIG. 9A is a top view of a shielding plate 900 in accordance with one ormore embodiments. Shielding plate 900 is an embodiment of firstshielding layer 114 shown in FIG. 1A and first shielding layer 314 shownin FIG. 3A. In some embodiments, shielding plate 900 of FIG. 9A is usedin place of or in conjunction with the first shielding layer 114 shownin FIG. 1A and the first shielding layer 314 shown in FIG. 3A.

Shielding plate 900 includes one or more horizontal portions 904 whichextend horizontally. In some embodiments, horizontal portions 904 aresubstantially parallel with other horizontal portions 904. Shieldingplate 900 includes one or more vertical portions 902 which extendvertically. In some embodiments, vertical portions 904 are substantiallyparallel with other vertical portions 904. Shielding plate 900 includesone or more openings 906. In some embodiments, openings 906 extend in asubstantially vertical direction. In some embodiments, openings 906extend in a substantially horizontal direction. In some embodiments,openings 906 extend in a combination of a vertical and horizontaldirection. In some embodiments, shielding plate 900 includes a solidconductor with openings 906, formed therein, shaped in various patterns,such as rectangular, square, circular, hexagonal, or other geometricshapes. In at least some embodiments, openings 906 are larger or smallerin size. In some embodiments, openings 906 provide protection fromelectromagnetic fields since they are small enough to reduce coupling atdesired operating frequencies. In some embodiments, openings 906 aresmaller than a wavelength for a corresponding frequency.

In some embodiments, shielding plate 900 is a multi-layer structure. Insome embodiments, shielding plate 900 is a multi-layer structure whichincludes one or more shielding plates formed with the same patternsoverlapping one another. In some embodiments, shielding plate 900 is amulti-layer structure which includes one or more shielding plates formedwith different patterns overlapping one another. In some embodiments,shielding plate 900 is a multi-layer structure which includes one ormore shielding plates which partially overlaps one another. In someembodiments, shielding plate 900 is a solid conductor with a plate-likeshape. In some embodiments, shielding plate 900 is a single-layerstructure.

FIG. 9B is a top view of a shielding plate 900′ in accordance with oneor more embodiments. Shielding plate 900′ is an embodiment of firstshielding layer 114 shown in FIG. 1A and first shielding layer 314 shownin FIG. 3A. In some embodiments, shielding plate 900′ of FIG. 9B is usedin place of or in conjunction with the first shielding layer 114 shownin FIG. 1A and the first shielding layer 314 shown in FIG. 3A.

Shielding plate 900′ includes one or more horizontal portions 910 whichextend horizontally. In some embodiments, horizontal portions 910 aresubstantially parallel with other horizontal portions 910. Shieldingplate 900′ includes one or more vertical portions 908 which extendvertically. In some embodiments, vertical portions 908 are substantiallyparallel with other vertical portions 908. Shielding plate 900′ includesone or more openings 912. In some embodiments, openings 912 extend in asubstantially vertical direction. In some embodiments, openings 912extend in a substantially horizontal direction. In some embodiments,openings 912 extend in a combination of a vertical and horizontaldirection. In some embodiments, shielding plate 900′ includes a solidconductor with openings 912, formed therein, shaped in various patterns,such as rectangular, square, circular, hexagonal, or other geometricshapes. In at least some embodiments, openings 912 are larger or smallerin size. In some embodiments, openings 912 provide protection fromelectromagnetic fields since they are small enough to reduce coupling atdesired operating frequencies. In some embodiments, openings 912 aresmaller than a wavelength for a corresponding frequency.

In some embodiments, shielding plate 900′ is a multi-layer structure. Insome embodiments, shielding plate 900′ is a multi-layer structure whichincludes one or more shielding plates formed with the same patternsoverlapping one another. In some embodiments, shielding plate 900′ is amulti-layer structure which includes one or more shielding plates formedwith different patterns overlapping one another. In some embodiments,shielding plate 900′ is a multi-layer structure which includes one ormore shielding plates which partially overlaps one another. In someembodiments, shielding plate 900′ is a solid conductor with a plate-likeshape. In some embodiments, shielding plate 900′ is a single-layerstructure.

FIG. 10 is a flow chart of a method 1000 of making an LC structure andan LC transmission line structure in accordance with one or moreembodiments. Method 1000 begins with operation 1002 in which a firstconductive structure, e.g., first conductive line 106 a (FIG. 1A) orfirst conductive line 306 a (FIG. 3A), is formed over a first substrate,e.g., first substrate 102 (FIG. 1A) or first substrate 302 (FIG. 3A). Insome embodiments, the first conductive line is formed using acombination of photolithography and etching processes to form openingsin an IMD layer, e.g., first IMD layer 104 (FIG. 1A) or first IMD layer304 (FIG. 3A). In some embodiments, the photolithography processincludes patterning a photoresist, such as a positive photoresist or anegative photoresist. In some embodiments, the photolithography processincludes forming a hard mask, an antireflective structure, or anothersuitable photolithography structure. In some embodiments, the etchingprocess is a wet etching process, a dry etching process, a reactive ionetching (RIE) process, or another suitable etching process. The openingsare then filled with conductive material, e.g., copper, aluminum,titanium, nickel, tungsten, or other suitable conductive material. Insome embodiments, the openings are filled using CVD, PVD, sputtering,atomic layer deposition (ALD) or other suitable formation process.

In some embodiments, operation 1002 is omitted. Operation 1002 isomitted, e.g., in embodiments which do not include a first conductiveline between the first substrate and a second substrate, e.g., LCstructure 200 and 600 (FIGS. 2A and 6A) and LC transmission linestructure 400 and 800 (FIGS. 4A and 8A).

Method 1000 continues with operation 1004 in which first shieldingstructure, e.g., first shielding structure 114 (FIG. 1A) or firstshielding structure 314 (FIG. 3A), is formed over the first substrate,e.g., first substrate 102 (FIG. 1A) or first substrate 302 (FIG. 3A). Insome embodiments, the first shielding structure is formed using acombination of photolithography and etching processes to form openingsin an IMD layer, e.g., first IMD layer 104 (FIG. 1A) or first IMD layer304 (FIG. 3A). In some embodiments, the photolithography processincludes patterning a photoresist, such as a positive photoresist or anegative photoresist. In some embodiments, the photolithography processincludes forming a hard mask, an antireflective structure, or anothersuitable photolithography structure. In some embodiments, the etchingprocess is a wet etching process, a dry etching process, an RIE process,or another suitable etching process. The openings are then filled withconductive material, e.g., copper, aluminum, titanium, nickel, tungsten,or other suitable conductive material. In some embodiments, the openingsare filled using CVD, PVD, sputtering, ALD or other suitable formationprocess.

In some embodiments, operation 1004 is omitted. Operation 1004 isomitted, e.g., in embodiments which do not include a first shieldinglayer between the first substrate and a second substrate, e.g., LCstructure 200 and 600 (FIGS. 2A and 6A) and LC transmission linestructure 400 and 800 (FIGS. 4A and 8A).

Method 1000 continues with operation 1006 in which first gate layer,e.g., first gate layer 118 (FIG. 1A) or first gate layer 318 (FIG. 3A),is formed over the first substrate, e.g., first substrate 102 (FIG. 1A)or first substrate 302 (FIG. 3A). In some embodiments, the first gatelayer is formed using a doped or non-doped polycrystalline silicon (orpolysilicon). Alternatively, the first gate layer includes a metal, suchas Al, Cu, W, Ti, Ta, TiN, TaN, NiSi, CoSi, other suitable conductivematerials, or combinations thereof, in some embodiments. In someembodiments, the first gate layer is formed using CVD, PVD, ALD,plating, or other suitable formation processes. In some embodiments, thefirst gate layer has a multilayer structure and is formed in amultiple-step process. Operation 1006 is omitted, e.g., in embodimentswhich do not include a first gate layer between the first substrate anda second substrate, e.g., LC structure 200 and 600 (FIGS. 2A and 6A) andLC transmission line structure 400 and 800 (FIGS. 4A and 8A).

Method 1000 continues with operation 1008 in which a second substrate,e.g., second substrate 120 (FIG. 1A) or second substrate 320 (FIG. 3A),is placed over the first substrate. In some embodiments, secondsubstrate includes polysilicon, doped silicon, or other suitableconductive materials.

Method 1000 continues with operation 1010 in which at least one switch,e.g., switch 122 (FIG. 1A) or switch 322 (FIG. 3A), is formed in thesecond substrate, e.g., second substrate 120 (FIG. 1A) or secondsubstrate 320 (FIG. 3A). In some embodiments, the at least one switch isa MOS, BJT, HEMT or another suitable switching element. In someembodiments, the at least one switch is formed through a combination ofimplantation processes, deposition process and etching processes. Insome embodiments, operation 1010 is omitted when a switch is notutilized.

Method 1000 continues with operation 1012 in which at least oneconductive line, e.g., conductive line 140 (FIG. 1A) or conductive line340 (FIG. 3A), is formed in the second substrate. In some embodiments,the conductive line is formed using a combination of photolithographyand material removal processes to form openings in the second substrate.In some embodiments, the photolithography process includes patterning aphotoresist, such as a positive photoresist or a negative photoresist.In some embodiments, the photolithography process includes forming ahard mask, an antireflective structure, or another suitablephotolithography structure. In some embodiments, the material removalprocess includes a wet etching process, a dry etching process, an RIEprocess, laser drilling or another suitable etching process. Theopenings are then filled with conductive material, e.g., copper,aluminum, titanium, nickel, tungsten, or other suitable conductivematerial. In some embodiments, the openings are filled using CVD, PVD,sputtering, ALD or other suitable formation process. In someembodiments, operation 1012 is omitted.

Method 1000 continues with operation 1014 in which second gate layer,e.g., second gate layer 128 (FIG. 1A) or second gate layer 328 (FIG.3A), is formed over the second substrate, e.g., second substrate 120(FIG. 1A) or second substrate 320 (FIG. 3A). In some embodiments, thesecond gate layer is formed using a doped or non-doped polycrystallinesilicon (or polysilicon). Alternatively, the second gate layer includesa metal, such as Al, Cu, W, Ti, Ta, TiN, TaN, NiSi, CoSi, other suitableconductive materials, or combinations thereof, in some embodiments. Insome embodiments, the second gate layer is formed using CVD, PVD, ALD,plating, or other suitable formation processes. In some embodiments, thesecond gate layer has a multilayer structure and is formed in amultiple-step process.

Operation 1014 is omitted, e.g., in embodiments which do not include asecond gate layer over the first substrate and a second substrate, e.g.,LC structure 200 and 600 (FIGS. 2B and 6B) and LC transmission linestructure 400 and 800 (FIGS. 4B and 8B).

Method 1000 continues with operation 1016 in which second shieldingstructure, e.g., second shielding structure 130 (FIG. 1A) or secondshielding structure 330 (FIG. 3A), is formed on the second substrate,e.g., second substrate 120 (FIG. 1A) or second substrate 320 (FIG. 3A).In some embodiments, the second shielding structure is formed using acombination of photolithography and etching processes to form openingsin an IMD layer, e.g., second IMD layer 126 (FIG. 1A) or second IMDlayer 326 (FIG. 3A). In some embodiments, the photolithography processincludes patterning a photoresist, such as a positive photoresist or anegative photoresist. In some embodiments, the photolithography processincludes forming a hard mask, an antireflective structure, or anothersuitable photolithography structure. In some embodiments, the etchingprocess is a wet etching process, a dry etching process, an RIE process,or another suitable etching process. The openings are then filled withconductive material, e.g., copper, aluminum, titanium, nickel, tungsten,or other suitable conductive material. In some embodiments, the openingsare filled using CVD, PVD, sputtering, ALD or other suitable formationprocess.

In some embodiments, operation 1016 is omitted. Operation 1016 isomitted, e.g., in embodiments which do not include a second shieldinglayer above the first substrate and second substrate, e.g., LC structure200 and 600 (FIGS. 2B and 6B) and LC transmission line structure 400 and800 (FIGS. 4B and 8B).

Method 1000 continues with operation 1018 in which a second conductivestructure, e.g., second conductive line 106 b (FIG. 1A) or secondconductive line 306 b (FIG. 3A), is formed on a second substrate, e.g.,second substrate 120 (FIG. 1A) or second substrate 320 (FIG. 3A). Insome embodiments, the second conductive line is formed using acombination of photolithography and etching processes to form openingsin an IMD layer, e.g., second IMD layer 126 (FIG. 1A) or second IMDlayer 326 (FIG. 3A). In some embodiments, the photolithography processincludes patterning a photoresist, such as a positive photoresist or anegative photoresist. In some embodiments, the photolithography processincludes forming a hard mask, an antireflective structure, or anothersuitable photolithography structure. In some embodiments, the etchingprocess is a wet etching process, a dry etching process, an RIE process,or another suitable etching process. The openings are then filled withconductive material, e.g., copper, aluminum, titanium, nickel, tungsten,or other suitable conductive material. In some embodiments, the openingsare filled using CVD, PVD, sputtering, ALD or other suitable formationprocess.

In some embodiments, operation 1018 is omitted. Operation 1018 isomitted, e.g., in embodiments which do not include a second conductiveline above the first substrate and second substrate, e.g., LC structure200 and 600 (FIGS. 2B and 6B) and LC transmission line structure 400 and800 (FIGS. 4B and 8B).

Method 1000 continues with operation 1020 in which the first substrateis bonded to the second substrate. In some embodiments, the firstsubstrate is bonded to the second substrate using a laser bondingprocess, a conductive adhesive layer, soldering process or anothersuitable bonding process.

One of ordinary skill in the art would recognize that an order ofoperations in method 1000 is adjustable. One of ordinary skill in theart would further recognize that additional steps are able to beincluded in method 1000 without departing from the scope of thisdescription.

One aspect of this description relates to a tank circuit structure. Thetank circuit structure includes a first gate layer, a first substrate, afirst shielding layer, a first conductive line and a first IMD layer.The first substrate is over the first gate layer. The first shieldinglayer is over the first substrate. The first conductive line is over thefirst shielding layer. The first IMD layer is between the firstsubstrate and the first conductive line.

Another aspect of this description relates to a tank circuit structure.The tank circuit structure includes a first gate layer, a firstsubstrate over the first gate layer, a first conductive line over thefirst gate layer, a first shielding layer over the first gate layer, asecond substrate below the first gate layer, and a first IMD layerbetween the first substrate and the second substrate.

Still another aspect of this description relates to a method of making atank circuit structure. The method including forming a first gate layerbelow a first substrate and over a second substrate, forming a firstconductive structure over the first gate layer, the first conductivestructure being an inductor or a transmission line, forming a firstshielding layer over the first gate layer, and forming an inter levelvia in the first substrate, and electrically connected to the first gatelayer.

It will be readily seen by one of ordinary skill in the art that thedisclosed embodiments fulfill one or more of the advantages set forthabove. After reading the foregoing specification, one of ordinary skillwill be able to affect various changes, substitutions of equivalents andvarious other embodiments as broadly disclosed herein. It is thereforeintended that the protection granted hereon be limited only by thedefinition contained in the appended claims and equivalents thereof.

What is claimed is:
 1. A tank circuit structure comprising: a first gatelayer; a first substrate over the first gate layer; a first shieldinglayer over the first substrate; a first conductive line over the firstshielding layer; a second gate layer between the first substrate and thefirst shielding layer; and a first inter metal dielectric (IMD) layerbetween the first substrate and the first conductive line.
 2. The tankcircuit structure of claim 1, further comprising a second substratebelow the first gate layer.
 3. The tank circuit structure of claim 1,wherein the first conductive line comprises a meandering conductiveline.
 4. The tank circuit structure of claim 1, wherein the firstconductive line comprises: a transmission line; or an inductor.
 5. Thetank circuit structure of claim 1, further comprising a secondconductive line on an opposite side of the first substrate from thefirst conductive line.
 6. The tank circuit structure of claim 5, furthercomprising a second shielding layer over the second conductive line. 7.The tank circuit structure of claim 5, further comprising at least oneswitch in the first substrate, wherein the at least one switch isconfigured to selectively couple the first conductive line to the secondconductive line.
 8. The tank circuit structure of claim 5, furthercomprising a third conductive line coupled to the first conductive lineand the second conductive line, wherein the first gate layer is coupledto the third conductive line.
 9. The tank circuit structure of claim 5,further comprising: a second IMD layer below the first substrate,wherein the second conductive line is in the second IMD layer.
 10. Thetank circuit structure of claim 5, further comprising an inter level viaconfigured to electrically couple the first conductive line to thesecond conductive line through the first substrate.
 11. A tank circuitstructure comprising: a first gate layer; a first substrate over thefirst gate layer; a first conductive line over the first gate layer; afirst shielding layer over the first gate layer; a second substratebelow the first gate layer; an inter level via extending through thefirst substrate; and a first inter metal dielectric (IMD) layer betweenthe first substrate and the second substrate.
 12. The tank circuitstructure of claim 11, wherein the inter level via is configured toelectrically connect the first gate layer to the first conductive line.13. The tank circuit structure of claim 11, wherein the first shieldinglayer comprises: a first conductive portion extending in a firstdirection; a second conductive portion extending in a second directiondifferent from the first direction, and intersecting the firstconductive portion; a third conductive portion extending in the seconddirection, separated from the second conductive portion in the firstdirection, and intersecting the first conductive portion; and a fourthconductive portion extending in the second direction, separated from thesecond conductive portion and the third conductive portion in the firstdirection, and intersecting the first conductive portion.
 14. The tankcircuit structure of claim 11, wherein the first conductive linecomprises a meandering conductive line.
 15. The tank circuit structureof claim 11, further comprising: a second gate layer over the firstsubstrate and below the first conductive line; and a second conductiveline on an opposite side of the first substrate from the firstconductive line.
 16. The tank circuit structure of claim 15, furthercomprising: a second shielding layer embedded in the WED layer, andbeing over the second substrate and the second conductive line.
 17. Amethod of making a tank circuit structure, the method comprising:forming a first gate layer below a first substrate and over a secondsubstrate; forming a first conductive structure over the first gatelayer, the first conductive structure being an inductor or atransmission line; forming a first shielding layer over the first gatelayer; and forming an inter level via in the first substrate, andelectrically connected to the first gate layer.
 18. The method of claim17, further comprising forming a second gate layer over the firstsubstrate and below the first conductive structure.
 19. The method ofclaim 18, further comprising: bonding the second substrate to the firstsubstrate; and forming a second conductive structure over the secondsubstrate; wherein the inter level via is further electrically connectedto the first conductive structure, and electrically connects the firstgate layer to the first conductive structure.
 20. The method of claim19, further comprising forming a second shielding structure over thesecond substrate and the second conductive structure.